getdns/src/dnssec.c

/**
 *
 * /brief function for DNSSEC
 *
 * The priv_getdns_get_validation_chain function is called after an answer
 * has been fetched when the dnssec_return_validation_chain extension is set.
 * It fetches DNSKEYs, DSes and their signatures for all RRSIGs found in the
 * answer.
 */

/*
 * Copyright (c) 2013, NLnet Labs, Verisign, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * * Neither the names of the copyright holders nor the
 *   names of its contributors may be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL Verisign, Inc. BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <unbound.h>
#include <ldns/ldns.h>
#include "getdns/getdns.h"
#include "config.h"
#include "context.h"
#include "util-internal.h"
#include "types-internal.h"
#include "dnssec.h"
#include "rr-dict.h"
#include "gldns/str2wire.h"
#include "gldns/wire2str.h"
#include "general.h"
#include "dict.h"

#if defined(SEC_DEBUG) && SEC_DEBUG
inline static void debug_sec_print_rr(const char *msg, priv_getdns_rr_iter *rr)
{
	char str_spc[8192], *str = str_spc;
	size_t str_len = sizeof(str_spc);
	uint8_t *data = rr->pos;
	size_t data_len = rr->nxt - rr->pos;

	if (!rr || !rr->pos) {
		DEBUG_SEC("%s<nil>\n", msg);
		return;
	}
	(void) gldns_wire2str_rr_scan(
	    &data, &data_len, &str, &str_len, rr->pkt, rr->pkt_end - rr->pkt);
	DEBUG_SEC("%s%s", msg, str_spc);
}
inline static void debug_sec_print_dname(const char *msg, uint8_t *label)
{
	char str[1024];

	if (gldns_wire2str_dname_buf(label, 256, str, sizeof(str)))
		DEBUG_SEC("%s%s\n", msg, str);
	else
		DEBUG_SEC("%s<nil>\n", msg);
}
#else
#define debug_sec_print_rr(...) DEBUG_OFF(__VA_ARGS__)
#define debug_sec_print_dname(...) DEBUG_OFF(__VA_ARGS__)
#endif


static inline uint16_t rr_iter_type(priv_getdns_rr_iter *rr)
{ return rr->rr_type + 2 <= rr->nxt ? gldns_read_uint16(rr->rr_type) : 0; }
static inline uint16_t rr_iter_class(priv_getdns_rr_iter *rr)
{ return rr->rr_type + 4 <= rr->nxt ? gldns_read_uint16(rr->rr_type + 2) : 0; }

static priv_getdns_rr_iter *rr_iter_ansauth(priv_getdns_rr_iter *rr)
{
	while (rr && rr->pos && !(
	    priv_getdns_rr_iter_section(rr) == GLDNS_SECTION_ANSWER ||
	    priv_getdns_rr_iter_section(rr) == GLDNS_SECTION_AUTHORITY))

		rr = priv_getdns_rr_iter_next(rr);

	return rr && rr->pos ? rr : NULL;
}

static int rr_owner_equal(priv_getdns_rr_iter *rr, uint8_t *name)
{
	uint8_t owner_spc[256], *owner;
	size_t  owner_len = sizeof(owner_spc);

	return (owner = priv_getdns_owner_if_or_as_decompressed(rr,  owner_spc
	                                                          , &owner_len))
	    && priv_getdns_dname_equal(owner, name);
}

static priv_getdns_rr_iter *rr_iter_name_class_type(priv_getdns_rr_iter *rr,
    uint8_t *name, uint16_t rr_class, uint16_t rr_type)
{
	while (rr_iter_ansauth(rr) && !(
	    rr_iter_type(rr)  == rr_type  &&
	    rr_iter_class(rr) == rr_class &&
	    rr_owner_equal(rr, name)))

		rr = priv_getdns_rr_iter_next(rr);

	return rr && rr->pos ? rr : NULL;
}

static priv_getdns_rr_iter *rr_iter_not_name_class_type(priv_getdns_rr_iter *rr,
    uint8_t *name, uint16_t rr_class, uint16_t rr_type)
{
	while (rr_iter_ansauth(rr) && (
	    rr_iter_type(rr)  == GETDNS_RRTYPE_RRSIG || (
	    rr_iter_type(rr)  == rr_type  &&
	    rr_iter_class(rr) == rr_class &&
	    rr_owner_equal(rr, name))))

		rr = priv_getdns_rr_iter_next(rr);
	
	return rr && rr->pos ? rr : NULL;
}

static priv_getdns_rr_iter *rr_iter_rrsig_covering(priv_getdns_rr_iter *rr,
    uint8_t *name, uint16_t rr_class, uint16_t rr_type)
{
	while (rr_iter_ansauth(rr) && !(
	    rr_iter_type(rr)  == GETDNS_RRTYPE_RRSIG &&
	    rr_iter_class(rr) == rr_class &&
	    rr->rr_type + 12 <= rr->nxt &&
	    gldns_read_uint16(rr->rr_type + 10) == rr_type && 
	    rr_owner_equal(rr, name)))

		rr = priv_getdns_rr_iter_next(rr);

	return rr && rr->pos ? rr : NULL;
}

typedef struct getdns_rrset {
	uint8_t            *name;
	uint16_t            rr_class;
	uint16_t            rr_type;
	getdns_network_req *netreq;
	uint8_t             name_spc[];
} getdns_rrset;

typedef struct rrtype_iter {
	priv_getdns_rr_iter  rr_i;
	getdns_rrset        *rrset;
} rrtype_iter;

typedef struct rrsig_iter {
	priv_getdns_rr_iter  rr_i;
	getdns_rrset        *rrset;
} rrsig_iter;

static rrtype_iter *rrtype_iter_next(rrtype_iter *i)
{
	return (rrtype_iter *) rr_iter_name_class_type(
	    priv_getdns_rr_iter_next(&i->rr_i),
	    i->rrset->name, i->rrset->rr_class, i->rrset->rr_type);
}

static rrtype_iter *rrtype_iter_init(rrtype_iter *i, getdns_rrset *rrset)
{
	i->rrset = rrset;
	return (rrtype_iter *) rr_iter_name_class_type(
	    priv_getdns_rr_iter_init(&i->rr_i, rrset->netreq->response
	                                     , rrset->netreq->response_len),
	    i->rrset->name, i->rrset->rr_class, i->rrset->rr_type);
}

static rrsig_iter *rrsig_iter_next(rrsig_iter *i)
{
	return (rrsig_iter *) rr_iter_rrsig_covering(
	    priv_getdns_rr_iter_next(&i->rr_i),
	    i->rrset->name, i->rrset->rr_class, i->rrset->rr_type);
}

static rrsig_iter *rrsig_iter_init(rrsig_iter *i, getdns_rrset *rrset)
{
	i->rrset = rrset;
	return (rrsig_iter *) rr_iter_rrsig_covering(
	    priv_getdns_rr_iter_init(&i->rr_i, rrset->netreq->response
	                                     , rrset->netreq->response_len),
	    i->rrset->name, i->rrset->rr_class, i->rrset->rr_type);
}

inline static int rrset_has_rrsigs(getdns_rrset *rrset)
{
	rrsig_iter rrsig;
	return rrsig_iter_init(&rrsig, rrset) != NULL;
}

#if defined(SEC_DEBUG) && SEC_DEBUG
static void debug_sec_print_rrset(const char *msg, getdns_rrset *rrset)
{
	char owner[1024];
	char buf_space[2048];
	gldns_buffer buf;
	rrtype_iter *rr, rr_space;
	rrsig_iter  *rrsig, rrsig_space;
	size_t i;

	if (!rrset) {
		DEBUG_SEC("<nil>");
		return;
	}
	gldns_buffer_init_frm_data(&buf, buf_space, sizeof(buf_space));
	if (gldns_wire2str_dname_buf(rrset->name, 256, owner, sizeof(owner)))
		gldns_buffer_printf(&buf, "%s ", owner);
	else	gldns_buffer_printf(&buf, "<nil> ");

	switch (rrset->rr_class) {
	case GETDNS_RRCLASS_IN	: gldns_buffer_printf(&buf, "IN ")  ; break;
	case GETDNS_RRCLASS_CH	: gldns_buffer_printf(&buf, "CH ")  ; break;
	case GETDNS_RRCLASS_HS	: gldns_buffer_printf(&buf, "HS ")  ; break;
	case GETDNS_RRCLASS_NONE: gldns_buffer_printf(&buf, "NONE "); break;
	case GETDNS_RRCLASS_ANY	: gldns_buffer_printf(&buf, "ANY ") ; break;
	default			: gldns_buffer_printf(&buf, "CLASS%d "
						          , rrset->rr_class);
				  break;
	}
	gldns_buffer_printf(&buf, "%s", priv_getdns_rr_type_name(rrset->rr_type));

	gldns_buffer_printf(&buf, ", rrs:");
	for ( rr = rrtype_iter_init(&rr_space, rrset), i = 1
	    ; rr
	    ; rr = rrtype_iter_next(rr), i++)
		gldns_buffer_printf(&buf, " %d", (int)i);

	gldns_buffer_printf(&buf, ", rrsigs:");
	for ( rrsig = rrsig_iter_init(&rrsig_space, rrset), i = 1
	    ; rrsig
	    ; rrsig = rrsig_iter_next(rrsig), i++)
		gldns_buffer_printf(&buf, " %d", (int)i);

	DEBUG_SEC("%s%s\n", msg, buf_space);
}
#else
#define debug_sec_print_rrset(...) DEBUG_OFF(__VA_ARGS__)
#endif



typedef struct rrset_iter rrset_iter;
struct rrset_iter {
	getdns_rrset        rrset;
	uint8_t             name_spc[256];
	size_t              name_len;
	priv_getdns_rr_iter rr_i;
};

static rrset_iter *rrset_iter_init(rrset_iter *i, getdns_network_req *netreq)
{
	priv_getdns_rr_iter *rr;

	i->rrset.name = i->name_spc;
	i->rrset.netreq = netreq;
	i->name_len = 0;

	for ( rr = priv_getdns_rr_iter_init(&i->rr_i
	                                   , netreq->response
	                                   , netreq->response_len)
	    ;(rr = rr_iter_ansauth(rr))
	    ; rr = priv_getdns_rr_iter_next(rr)) {

		if ((i->rrset.rr_type = rr_iter_type(rr))
		    == GETDNS_RRTYPE_RRSIG)
			continue;

		i->rrset.rr_class = rr_iter_class(rr);

		if (!(i->rrset.name = priv_getdns_owner_if_or_as_decompressed(
		    rr, i->name_spc, &i->name_len)))
			continue;

		return i;
	}
	return NULL;
}


static rrset_iter *rrset_iter_next(rrset_iter *i)
{
	priv_getdns_rr_iter *rr;

	if (!(rr = i && i->rr_i.pos ? &i->rr_i : NULL))
		return NULL;

	if (!(rr = rr_iter_not_name_class_type(rr,
	    i->rrset.name, i->rrset.rr_class, i->rrset.rr_type)))
		return NULL;

	i->rrset.rr_type  = rr_iter_type(rr);
	i->rrset.rr_class = rr_iter_class(rr);
	if (!(i->rrset.name = priv_getdns_owner_if_or_as_decompressed(
		    rr, i->name_spc, &i->name_len)))
		return rrset_iter_next(i);

	return i;
}

static getdns_rrset *rrset_iter_value(rrset_iter *i)
{
	if (!i)
		return NULL;
	if (!i->rr_i.pos)
		return NULL;
	return &i->rrset;
}

typedef struct chain_head chain_head;
typedef struct chain_node chain_node;

struct chain_head {
	struct mem_funcs  my_mf;

	chain_head       *next;
	chain_node       *parent;
	size_t            node_count; /* Number of nodes attached directly
	                               * to this head.  For cleaning.  */
	getdns_rrset      rrset;
	uint8_t           name_spc[];
};

struct chain_node {
	chain_node  *parent;
	
	getdns_rrset dnskey;
	getdns_rrset ds    ;
	getdns_rrset soa   ;

	chain_head  *chains;
};

static size_t count_outstanding_requests(chain_head *head)
{
	size_t count;
	chain_node *node;

	if (!head)
		return 0;

	for ( node = head->parent, count = 0
	    ; node
	    ; node = node->parent) {

		if (node->dnskey.netreq &&
		    node->dnskey.netreq->state != NET_REQ_FINISHED &&
		    node->dnskey.netreq->state != NET_REQ_CANCELED)
			count++;

		if (node->ds.netreq &&
		    node->ds.netreq->state != NET_REQ_FINISHED &&
		    node->ds.netreq->state != NET_REQ_CANCELED)
			count++;

		if (node->soa.netreq &&
		    node->soa.netreq->state != NET_REQ_FINISHED &&
		    node->soa.netreq->state != NET_REQ_CANCELED)
			count++;
	}
	return count + count_outstanding_requests(head->next);
}

static void append_rrs2val_chain_list(getdns_context *ctxt,
    getdns_list *val_chain_list, getdns_network_req *netreq)
{
	rrset_iter *i, i_spc;
	getdns_rrset *rrset;
	rrtype_iter *rr, rr_spc;
	rrsig_iter  *rrsig, rrsig_spc;
	getdns_dict *rr_dict;

	for (i = rrset_iter_init(&i_spc, netreq); i; i = rrset_iter_next(i)) {
		rrset = rrset_iter_value(i);

		if (rrset->rr_type != GETDNS_RRTYPE_DNSKEY &&
		    rrset->rr_type != GETDNS_RRTYPE_DS     &&
		    rrset->rr_type != GETDNS_RRTYPE_NSEC   &&
		    rrset->rr_type != GETDNS_RRTYPE_NSEC3)
			continue;

		for ( rr = rrtype_iter_init(&rr_spc, rrset)
		    ; rr; rr = rrtype_iter_next(rr)) {

			rr_dict = priv_getdns_rr_iter2rr_dict(ctxt, &rr->rr_i);
			if (!rr_dict) continue;

			(void)getdns_list_append_dict(val_chain_list, rr_dict);
			getdns_dict_destroy(rr_dict);
		}
		for ( rrsig = rrsig_iter_init(&rrsig_spc, rrset)
		    ; rrsig; rrsig = rrsig_iter_next(rrsig)) {

			rr_dict=priv_getdns_rr_iter2rr_dict(ctxt,&rrsig->rr_i);
			if (!rr_dict) continue;

			(void)getdns_list_append_dict(val_chain_list, rr_dict);
			getdns_dict_destroy(rr_dict);
		}
	}
}

static void check_chain_complete(chain_head *chain)
{
	getdns_dns_req *dnsreq;
	size_t o, node_count;
	chain_head *head, *next;
	chain_node *node;
	getdns_list *val_chain_list;
	getdns_dict *response_dict;

	if ((o = count_outstanding_requests(chain)) > 0) {
		DEBUG_SEC("%zu outstanding requests\n", o);
		return;
	}
	DEBUG_SEC("Chain done!\n");
	dnsreq = chain->rrset.netreq->owner;
	/* TODO: DNSSEC validation of netreq! */

	val_chain_list = dnsreq->dnssec_return_validation_chain
		? getdns_list_create_with_context(dnsreq->context) : NULL;

	/* Cleanup the chain */
	for ( head = chain; head ; head = next ) {
		next = head->next;
		for ( node_count = head->node_count, node = head->parent
		    ; node_count
		    ; node_count--, node = node->parent ) {

			if (node->dnskey.netreq) {
				append_rrs2val_chain_list(dnsreq->context,
				    val_chain_list, node->dnskey.netreq);
				dns_req_free(node->dnskey.netreq->owner);
			}
			if (node->ds.netreq) {
				append_rrs2val_chain_list(dnsreq->context,
				    val_chain_list, node->ds.netreq);
				dns_req_free(node->ds.netreq->owner);
			}
		}
		GETDNS_FREE(head->my_mf, head);
	}

	response_dict = create_getdns_response(dnsreq);
	if (val_chain_list) {
		(void) getdns_dict_set_list(
		    response_dict, "validation_chain", val_chain_list);
		getdns_list_destroy(val_chain_list);
	}
	/* Final user callback */
	priv_getdns_call_user_callback(dnsreq, response_dict);
}

static void val_chain_node_soa_cb(getdns_dns_req *dnsreq);
static void val_chain_sched_soa_node(chain_node *node)
{
	getdns_context *context;
	getdns_eventloop *loop;
	getdns_dns_req *dnsreq;
	char  name[1024];

	context = node->chains->rrset.netreq->owner->context;
	loop    = node->chains->rrset.netreq->owner->loop;

	if (!gldns_wire2str_dname_buf(node->soa.name, 256, name, sizeof(name)))
		return;

	if (! node->soa.netreq &&
	    ! priv_getdns_general_loop(context, loop, name, GETDNS_RRTYPE_SOA,
	    dnssec_ok_checking_disabled, node, &dnsreq, NULL,
	    val_chain_node_soa_cb))

		node->soa.netreq = *dnsreq->netreqs;
}

static void val_chain_sched_soa(chain_head *head, uint8_t *dname)
{
	chain_node *node;

	if (!*dname)
		return;

	for ( node = head->parent
	    ; node && !priv_getdns_dname_equal(dname, node->dnskey.name)
	    ; node = node->parent);

	if (node)
		val_chain_sched_soa_node(node);
}

static void val_chain_node_cb(getdns_dns_req *dnsreq);
static void val_chain_sched_node(chain_node *node)
{
	getdns_context *context;
	getdns_eventloop *loop;
	getdns_dns_req *dnsreq;
	char  name[1024];

	context = node->chains->rrset.netreq->owner->context;
	loop    = node->chains->rrset.netreq->owner->loop;

	if (!gldns_wire2str_dname_buf(node->dnskey.name, 256, name, sizeof(name)))
		return;

	DEBUG_SEC("schedule DS & DNSKEY lookup for %s\n", name);

	if (! node->dnskey.netreq /* not scheduled */ &&
	    ! priv_getdns_general_loop(context, loop, name, GETDNS_RRTYPE_DNSKEY,
	    dnssec_ok_checking_disabled, node, &dnsreq, NULL, val_chain_node_cb))

		node->dnskey.netreq = *dnsreq->netreqs;

	if (! node->ds.netreq && node->parent /* not root */ &&
	    ! priv_getdns_general_loop(context, loop, name, GETDNS_RRTYPE_DS,
	    dnssec_ok_checking_disabled, node, &dnsreq, NULL, val_chain_node_cb))

		node->ds.netreq = *dnsreq->netreqs;
}

static void val_chain_sched(chain_head *head, uint8_t *dname)
{
	chain_node *node;

	for ( node = head->parent
	    ; node && !priv_getdns_dname_equal(dname, node->dnskey.name)
	    ; node = node->parent);
	if (node)
		val_chain_sched_node(node);
}

static void val_chain_sched_signer_node(chain_node *node, rrsig_iter *rrsig)
{
	priv_getdns_rdf_iter rdf_spc, *rdf;
	uint8_t signer_spc[256], *signer;
	size_t signer_len;
	
	if (!(rdf = priv_getdns_rdf_iter_init_at(&rdf_spc, &rrsig->rr_i, 7)))
		return;

	if (!(signer = priv_getdns_rdf_if_or_as_decompressed(
	    rdf, signer_spc, &signer_len)))
		return;

	while (node && !priv_getdns_dname_equal(signer, node->dnskey.name))
		node = node->parent;
	if (node)
		val_chain_sched_node(node);
}

static void val_chain_sched_signer(chain_head *head, rrsig_iter *rrsig)
{
	val_chain_sched_signer_node(head->parent, rrsig);
}

static void val_chain_node_cb(getdns_dns_req *dnsreq)
{
	chain_node *node = (chain_node *)dnsreq->user_pointer;
	getdns_network_req *netreq = dnsreq->netreqs[0];
	rrset_iter *i, i_spc;
	getdns_rrset *rrset;
	rrsig_iter  *rrsig, rrsig_spc;

	getdns_context_clear_outbound_request(dnsreq);
	switch (netreq->request_type) {
	case GETDNS_RRTYPE_DS    : break;
	case GETDNS_RRTYPE_DNSKEY: node->dnskey.netreq = netreq;
	default                  : check_chain_complete(node->chains);
				   return;
	}
	for (i = rrset_iter_init(&i_spc, netreq); i; i = rrset_iter_next(i)) {
		rrset = rrset_iter_value(i);

		if (rrset->rr_type != GETDNS_RRTYPE_DS     &&
		    rrset->rr_type != GETDNS_RRTYPE_NSEC   &&
		    rrset->rr_type != GETDNS_RRTYPE_NSEC3)
			continue;

		for ( rrsig = rrsig_iter_init(&rrsig_spc, rrset)
		    ; rrsig; rrsig = rrsig_iter_next(rrsig))

			val_chain_sched_signer_node(node, rrsig);
	}
	check_chain_complete(node->chains);
}


static getdns_rrset *rrset_by_type(
    rrset_iter *i_spc, getdns_network_req *netreq, uint16_t rr_type)
{
	rrset_iter   *i;
	getdns_rrset *rrset;

	for (i = rrset_iter_init(i_spc, netreq); i; i = rrset_iter_next(i)) {
		rrset = rrset_iter_value(i);
		if (rrset->rr_type == rr_type)
			return rrset;
	}
	return NULL;
}

static void val_chain_node_soa_cb(getdns_dns_req *dnsreq)
{
	chain_node *node = (chain_node *)dnsreq->user_pointer;
	getdns_network_req *netreq = dnsreq->netreqs[0];
	rrset_iter i_spc;
	getdns_rrset *rrset;

	getdns_context_clear_outbound_request(dnsreq);

	if ((rrset = rrset_by_type(&i_spc, netreq, GETDNS_RRTYPE_SOA))) {

		while (node &&
		    ! priv_getdns_dname_equal(node->soa.name, rrset->name))
			node = node->parent;

		val_chain_sched_node(node);
	} else
		val_chain_sched_soa_node(node->parent);

	check_chain_complete(node->chains);
}

static int is_subdomain(
    const uint8_t * const subdomain, const uint8_t *domain)
{
	while (*domain) {
		if (priv_getdns_dname_equal(subdomain, domain))
			return 1;

		domain += *domain + 1;
	}
	return *subdomain == 0;
}

static uint8_t **reverse_labels(uint8_t *dname, uint8_t **labels)
{
	if (*dname)
		labels = reverse_labels(dname + *dname + 1, labels);
	*labels = dname;
	return labels + 1;
}

static chain_head *add_rrset2val_chain(
    struct mem_funcs *mf, chain_head **chain_p, getdns_rrset *rrset)
{
	chain_head *head;
	uint8_t    *labels[128], **last_label, **label;

	size_t      max_labels; /* max labels in common */
	chain_head *max_head;
	chain_node *max_node;

	size_t      dname_len, head_sz, node_count, n;
	uint8_t    *dname, *region;
	chain_node *node;

	last_label = reverse_labels(rrset->name, labels);

	/* Try to find a chain with the most overlapping labels.
	 * max_labels will be the number of labels in common from the root
	 *            (so at least one; the root)
	 * max_head   will be the head of the chain with max # labebs in common
	 */
	max_head = NULL;
	max_labels = 0;
	for (head = *chain_p; head; head = head->next) {
		for (label = labels; label < last_label; label++) {
			if (! is_subdomain(*label, head->rrset.name))
				break;
		}
		if (label - labels > max_labels) {
			max_labels = label - labels;
			max_head = head;
		}
	}
	/* Chain found.  Now set max_node to the point in the chain where nodes
	 *               will be common.
	 */
	if (max_head) {
		for ( node = max_head->parent, n = 0
		    ; node
		    ; node = node->parent, n++);

		for ( n -= max_labels, node = max_head->parent
		    ; n
		    ; n--, node = node->parent);
	} else
		max_node = NULL;

	/* node_count is the amount of nodes to still allocate.
	 * the last one's parent has to hook into the max_node.
	 */
	dname_len = *labels - last_label[-1] + 1;
	head_sz = (sizeof(chain_head) + dname_len + 7) / 8 * 8;
	node_count = last_label - labels - max_labels;
	DEBUG_SEC( "%zu labels in common. %zu labels to allocate\n"
	         , max_labels, node_count);

	if (! (region = GETDNS_XMALLOC(*mf, uint8_t, head_sz + 
	    node_count * sizeof(chain_node))))
		return NULL;
	
	/* Append the head on the linked list of heads */
	for (head = *chain_p; head && head->next; head = head->next);
	if  (head)
		head = head->next = (chain_head *)region;
	else
		head = *chain_p   = (chain_head *)region;

	head->my_mf = *mf;
	head->next = NULL;
	head->rrset.name = head->name_spc;
	memcpy(head->name_spc, rrset->name, dname_len);
	head->rrset.rr_class = rrset->rr_class;
	head->rrset.rr_type = rrset->rr_type;
	head->rrset.netreq = rrset->netreq;
	head->node_count = node_count;

	if (!node_count) {
		head->parent = max_head->parent;
		return head;
	}

	/* Initialize the nodes */
	node = (chain_node *)(region + head_sz);
	head->parent = node;

	for ( node = (chain_node *)(region + head_sz), head->parent = node
	                                             , dname = head->rrset.name
	    ; node_count
	    ; node_count--, node = node->parent =&node[1], dname += *dname + 1) {

		node->chains          = *chain_p;
		node->ds.name         = dname;
		node->dnskey.name     = dname;
		node->soa.name        = dname;
		node->ds.rr_class     = head->rrset.rr_class;
		node->dnskey.rr_class = head->rrset.rr_class;
		node->soa.rr_class    = head->rrset.rr_class;
		node->ds.rr_type      = GETDNS_RRTYPE_DS;
		node->dnskey.rr_type  = GETDNS_RRTYPE_DNSKEY;
		node->soa.rr_type     = GETDNS_RRTYPE_SOA;
		node->ds.netreq       = NULL;
		node->dnskey.netreq   = NULL;
		node->soa.netreq      = NULL;

		node->soa.rr_class = head->rrset.rr_class;
	}
	/* On the first chain, max_node == NULL.
	 * Schedule a root DNSKEY query, we always need that.
	 */
	if (!(node[-1].parent = max_node))
		val_chain_sched(head, (uint8_t *)"\0");

	return head;
}

static void add_netreq2val_chain(
    chain_head **chain_p, getdns_network_req *netreq)
{
	rrset_iter *i, i_spc;
	getdns_rrset *rrset;
	rrsig_iter *rrsig, rrsig_spc;
	size_t n_rrsigs;
	chain_head *head;
	struct mem_funcs *mf;
	getdns_rrset empty_rrset;

	assert(netreq->response);
	assert(netreq->response_len >= GLDNS_HEADER_SIZE);

	mf = priv_getdns_context_mf(netreq->owner->context);

	/* On empty packet, find SOA (zonecut) for the qname and query DS */

	/* For all things with signatures, create a chain */

	/* For all things without signature, find SOA (zonecut) and query DS */

	if (GLDNS_ANCOUNT(netreq->response) == 0 &&
	    GLDNS_NSCOUNT(netreq->response) == 0) {

		empty_rrset.name = netreq->query + GLDNS_HEADER_SIZE;
		empty_rrset.rr_class = GETDNS_RRCLASS_IN;
		empty_rrset.rr_type  = 0;
		empty_rrset.netreq   = netreq;

		head = add_rrset2val_chain(mf, chain_p, &empty_rrset);
		val_chain_sched_soa(head, empty_rrset.name);
		return;
	}
	for (i = rrset_iter_init(&i_spc, netreq); i; i = rrset_iter_next(i)) {
		rrset = rrset_iter_value(i);
		debug_sec_print_rrset("rrset: ", rrset);

		head = add_rrset2val_chain(mf, chain_p, rrset);
		for ( rrsig = rrsig_iter_init(&rrsig_spc, rrset), n_rrsigs = 0
		    ; rrsig
		    ; rrsig = rrsig_iter_next(rrsig), n_rrsigs++) {
			
			val_chain_sched_signer(head, rrsig);
		}
		if (n_rrsigs)
			continue;

		if (rrset->rr_type == GETDNS_RRTYPE_SOA)
			val_chain_sched(head, rrset->name);
		else
			val_chain_sched_soa(head, rrset->name);
	}
}

static void get_val_chain(getdns_dns_req *dnsreq)
{
	getdns_network_req *netreq, **netreq_p;
	chain_head *chain = NULL;

	for (netreq_p = dnsreq->netreqs; (netreq = *netreq_p) ; netreq_p++)
		add_netreq2val_chain(&chain, netreq);

	if (chain)
		check_chain_complete(chain);
	else
		priv_getdns_call_user_callback(dnsreq,
		    create_getdns_response(dnsreq));
}

/******************************************************************************/
/*****************************                  *******************************/
/*****************************  NEW CHAIN CODE  *******************************/
/*****************************     (above)      *******************************/
/*****************************                  *******************************/
/******************************************************************************/

void priv_getdns_get_validation_chain(getdns_dns_req *dns_req)
{
	get_val_chain(dns_req);
}

/********************** functions for validate_dnssec *************************/

static getdns_return_t
priv_getdns_create_rr_from_dict(getdns_dict *rr_dict, ldns_rr **rr)
{
	gldns_buffer buf;
	uint8_t space[8192], *xspace = NULL;
	size_t xsize, pos = 0;
	ldns_status s;
	getdns_return_t r;

	gldns_buffer_init_frm_data(&buf, space, sizeof(space));
	if ((r = priv_getdns_rr_dict2wire(rr_dict, &buf)))
		return r;

	if ((xsize = gldns_buffer_position(&buf)) > sizeof(space)) {
		if (!(xspace = GETDNS_XMALLOC(rr_dict->mf, uint8_t, xsize)))
			return GETDNS_RETURN_MEMORY_ERROR;

		gldns_buffer_init_frm_data(&buf, xspace, xsize);
		if ((r = priv_getdns_rr_dict2wire(rr_dict, &buf))) {
			GETDNS_FREE(rr_dict->mf, xspace);
			return r;
		}
	}
	s = ldns_wire2rr(rr, gldns_buffer_begin(&buf),
	    gldns_buffer_position(&buf), &pos, GLDNS_SECTION_ANSWER);
	if (xspace)
		GETDNS_FREE(rr_dict->mf, xspace);
	return s ? GETDNS_RETURN_GENERIC_ERROR : GETDNS_RETURN_GOOD;
}
	
static getdns_return_t
priv_getdns_rr_list_from_list(getdns_list *list, ldns_rr_list **rr_list)
{
	getdns_return_t r;
	size_t i, l;
	struct getdns_dict *rr_dict;
	ldns_rr *rr;

	if ((r = getdns_list_get_length(list, &l)))
		return r;

	if (! (*rr_list = ldns_rr_list_new()))
		return GETDNS_RETURN_MEMORY_ERROR;

	for (i = 0; i < l; i++) {
		if ((r = getdns_list_get_dict(list, i, &rr_dict)))
			break;

		if ((r = priv_getdns_create_rr_from_dict(rr_dict, &rr)))
			break;

		if (! ldns_rr_list_push_rr(*rr_list, rr)) {
			ldns_rr_free(rr);
			r = GETDNS_RETURN_GENERIC_ERROR;
			break;
		}
	}
	if (r)
		ldns_rr_list_deep_free(*rr_list);
	return r;
}

static int
ldns_dname_compare_v(const void *a, const void *b) {
	return ldns_dname_compare((ldns_rdf *)a, (ldns_rdf *)b);
}

ldns_status
priv_getdns_ldns_dnssec_zone_add_rr(ldns_dnssec_zone *zone, ldns_rr *rr)
{
	ldns_dnssec_name *new_name;
	ldns_rbnode_t *new_node;

	if (ldns_rr_get_type(rr) != LDNS_RR_TYPE_NSEC3)
		return ldns_dnssec_zone_add_rr(zone, rr);
	
	if (!(new_name = ldns_dnssec_name_new()))
		return LDNS_STATUS_MEM_ERR;

	new_name->name = ldns_rdf_clone(ldns_rr_owner(rr));
	new_name->hashed_name = ldns_dname_label(ldns_rr_owner(rr), 0);
	new_name->name_alloced = true;

	if (!(new_node = LDNS_MALLOC(ldns_rbnode_t))) {
		ldns_dnssec_name_free(new_name);
		return LDNS_STATUS_MEM_ERR;
	}
	new_node->key = new_name->name;
	new_node->data = new_name;
	if (!zone->names)
		zone->names = ldns_rbtree_create(ldns_dname_compare_v);
	(void)ldns_rbtree_insert(zone->names, new_node);

#ifdef LDNS_DNSSEC_ZONE_HASHED_NAMES
	if (!(new_node = LDNS_MALLOC(ldns_rbnode_t))) {
		ldns_dnssec_name_free(new_name);
		return LDNS_STATUS_MEM_ERR;
	}
	new_node->key = new_name->hashed_name;
	new_node->data = new_name;
	if (!zone->hashed_names) {
		zone->_nsec3params = rr;
		zone->hashed_names = ldns_rbtree_create(ldns_dname_compare_v);
	}
	(void)ldns_rbtree_insert(zone->hashed_names, new_node);
#endif

	return ldns_dnssec_zone_add_rr(zone, rr);
}

static getdns_return_t
priv_getdns_dnssec_zone_from_list(struct getdns_list *list,
    ldns_dnssec_zone **zone)
{
	getdns_return_t r;
	size_t i, l;
	struct getdns_dict *rr_dict;
	ldns_rr *rr;
	ldns_status s;

	if ((r = getdns_list_get_length(list, &l)))
		return r;

	if (! (*zone = ldns_dnssec_zone_new()))
		return GETDNS_RETURN_MEMORY_ERROR;

	for (i = 0; i < l; i++) {
		if ((r = getdns_list_get_dict(list, i, &rr_dict)))
			break;

		if ((r = priv_getdns_create_rr_from_dict(rr_dict, &rr)))
			break;

		if ((s = priv_getdns_ldns_dnssec_zone_add_rr(*zone, rr))) {
			ldns_rr_free(rr);
			r = GETDNS_RETURN_GENERIC_ERROR;
			break;
		}
	}
	if (r)
		ldns_dnssec_zone_free(*zone);
	return r;
}

typedef struct zone_iter {
	ldns_dnssec_zone   *zone;
	ldns_rbnode_t      *cur_node;
	ldns_dnssec_rrsets *cur_rrset;

	ldns_dnssec_rrsets nsec_rrset;
	ldns_dnssec_rrs    nsec_rrs;
} zone_iter;

static void
rrset_iter_init_zone(zone_iter *i, ldns_dnssec_zone *zone)
{	
	ldns_dnssec_name *name;
	assert(i);

	i->zone = zone;
	if ((i->cur_node = zone->names
	                 ? ldns_rbtree_first(zone->names)
	                 : LDNS_RBTREE_NULL) == LDNS_RBTREE_NULL) {

		i->cur_rrset = NULL;
		return;
	}

	i->cur_rrset = ((ldns_dnssec_name *)i->cur_node->data)->rrsets;
	if (!i->cur_rrset) {
		name = ((ldns_dnssec_name *)i->cur_node->data);
		if (name->nsec && name->nsec_signatures) {
			i->cur_rrset = &i->nsec_rrset;
			i->nsec_rrset.rrs = &i->nsec_rrs;
			i->nsec_rrs.rr = name->nsec;
			i->nsec_rrs.next = NULL;
			i->nsec_rrset.type = ldns_rr_get_type(name->nsec);
			i->nsec_rrset.signatures =
				name->nsec_signatures;
			i->nsec_rrset.next = NULL;
			return;
		}
	}
}

static ldns_dnssec_rrsets *
_rrset_iter_value(zone_iter *i)
{
	assert(i);

	return i->cur_rrset;
}

static void
_rrset_iter_next(zone_iter *i)
{
	int was_nsec_rrset;
	ldns_dnssec_name *name;
	assert(i);

	if (! i->cur_rrset)
		return;

	was_nsec_rrset = (i->cur_rrset == &i->nsec_rrset);
	if (!  (i->cur_rrset = i->cur_rrset->next)) {

		if (!was_nsec_rrset) {
			name = ((ldns_dnssec_name *)i->cur_node->data);
			if (name->nsec && name->nsec_signatures) {
				i->cur_rrset = &i->nsec_rrset;
				i->nsec_rrset.rrs = &i->nsec_rrs;
				i->nsec_rrs.rr = name->nsec;
				i->nsec_rrs.next = NULL;
				i->nsec_rrset.type = ldns_rr_get_type(name->nsec);
				i->nsec_rrset.signatures =
					name->nsec_signatures;
				i->nsec_rrset.next = NULL;
				return;
			}
		}
		i->cur_node  = ldns_rbtree_next(i->cur_node);
		i->cur_rrset = i->cur_node != LDNS_RBTREE_NULL
		    ? ((ldns_dnssec_name *)i->cur_node->data)->rrsets
		    : NULL;
	}
}

static ldns_rr_list *
rrs2rr_list(ldns_dnssec_rrs *rrs)
{
	ldns_rr_list *r = ldns_rr_list_new();
	if (r)
		while (rrs) {
			(void) ldns_rr_list_push_rr(r, rrs->rr);
			rrs = rrs->next;
		}
	return r;
}

static ldns_status
verify_rrset(ldns_dnssec_rrsets *rrset_and_sigs,
    const ldns_rr_list *keys, ldns_rr_list *good_keys)
{
	ldns_status s;
	ldns_rr_list *rrset = rrs2rr_list(rrset_and_sigs->rrs);
	ldns_rr_list *sigs  = rrs2rr_list(rrset_and_sigs->signatures);
	s = ldns_verify(rrset, sigs, keys, good_keys);
#if 0
	if (s != 0) {
		fprintf(stderr, "verify status %d\nrrset: ", s);
		ldns_rr_list_print(stderr, rrset);
		fprintf(stderr, "\nsigs: ");
		ldns_rr_list_print(stderr, sigs);
		fprintf(stderr, "\nkeys: ");
		ldns_rr_list_print(stderr, keys);
		fprintf(stderr, "\n\n");
	}
#endif
	ldns_rr_list_free(sigs);
	ldns_rr_list_free(rrset);
	return s;
}

static ldns_status
chase(ldns_dnssec_rrsets *rrset, ldns_dnssec_zone *support,
    ldns_rr_list *support_keys, ldns_rr_list *trusted)
{
	ldns_status s;
	ldns_rr_list *verifying_keys;
	size_t i, j;
	ldns_rr *rr;
	ldns_dnssec_rrsets *key_rrset;
	ldns_dnssec_rrs *rrs;

	/* Secure by trusted keys? */
	s = verify_rrset(rrset, trusted, NULL);
	if (s == 0)
		return s;

	/* No, chase with support records..
	 * Is there a verifying key in the support records?
	 */
	verifying_keys = ldns_rr_list_new();
	s = verify_rrset(rrset, support_keys, verifying_keys);
	if (s != 0)
		goto done_free_verifying_keys;

	/* Ok, we have verifying keys from the support records.
	 * Compare them with the *trusted* keys or DSes,
	 * or chase them further down the validation chain.
	 */
	for (i = 0; i < ldns_rr_list_rr_count(verifying_keys); i++) {
		/* Lookup the rrset for key rr from the support records */
		rr = ldns_rr_list_rr(verifying_keys, i);
		key_rrset = ldns_dnssec_zone_find_rrset(
		    support, ldns_rr_owner(rr), ldns_rr_get_type(rr));
		if (! key_rrset) {
			s = LDNS_STATUS_CRYPTO_NO_DNSKEY;
			break;
		}
		/* When we signed ourselves, we have to cross domain border
		 * and look for a matching DS signed by a parents key
		 */
		if (rrset == key_rrset) {
			/* Is the verifying key trusted?
			 * (i.e. DS in trusted)
			 */
			for (j = 0; j < ldns_rr_list_rr_count(trusted); j++)
				if (ldns_rr_compare_ds(ldns_rr_list_rr(
				    trusted, j), rr))
					break;
			/* If so, check for the next verifying key
			 * (or exit SECURE)
			 */
			if (j < ldns_rr_list_rr_count(trusted))
				continue;

			/* Search for a matching DS in the support records */
			key_rrset = ldns_dnssec_zone_find_rrset(
			    support, ldns_rr_owner(rr), LDNS_RR_TYPE_DS);
			if (! key_rrset) {
				s = LDNS_STATUS_CRYPTO_NO_DNSKEY;
				break;
			}
			/* Now check if DS matches the DNSKEY! */
			for (rrs = key_rrset->rrs; rrs; rrs = rrs->next)
				if (ldns_rr_compare_ds(rr, rrs->rr))
					break;
			/* No DS found, try one of the other keys */
			if (! rrs)
				continue;
		}
		/* Pursue the chase with the verifying key (or its DS)
		 * and we're done.
		 */
		s = chase(key_rrset, support, support_keys, trusted);
		break;
	}
	if (i == ldns_rr_list_rr_count(verifying_keys))
		s = LDNS_STATUS_CRYPTO_NO_DNSKEY;
done_free_verifying_keys:
	ldns_rr_list_free(verifying_keys);
	return s;
}

/*
 * getdns_validate_dnssec
 *
 */
getdns_return_t
getdns_validate_dnssec(getdns_list *records_to_validate,
    getdns_list *support_records,
    getdns_list *trust_anchors)
{
	getdns_return_t r;
	ldns_rr_list     *trusted;
	ldns_dnssec_zone *support;
	ldns_rr_list     *support_keys;
	ldns_dnssec_zone *to_validate;
	zone_iter i;
	ldns_dnssec_rrsets *rrset;
	ldns_dnssec_rrs *rrs;
	ldns_status s = LDNS_STATUS_ERR;

	if ((r = priv_getdns_rr_list_from_list(trust_anchors, &trusted)))
		return r;

	if ((r = priv_getdns_dnssec_zone_from_list(
	    support_records, &support)))
		goto done_free_trusted;

	if ((r = priv_getdns_dnssec_zone_from_list(
	    records_to_validate, &to_validate)))
		goto done_free_support;

	if (! (support_keys = ldns_rr_list_new())) {
		r = GETDNS_RETURN_MEMORY_ERROR;
		goto done_free_to_validate;
	}
	/* Create a rr_list of all the keys in the support records */
	for (rrset_iter_init_zone(&i, support);
	    (rrset = _rrset_iter_value(&i)); _rrset_iter_next(&i))

		if (ldns_dnssec_rrsets_type(rrset) == LDNS_RR_TYPE_DS ||
		    ldns_dnssec_rrsets_type(rrset) == LDNS_RR_TYPE_DNSKEY)

			for (rrs = rrset->rrs; rrs; rrs = rrs->next)
				(void) ldns_rr_list_push_rr(
				    support_keys, rrs->rr);

	/* Now walk through the rrsets to validate */
	for (rrset_iter_init_zone(&i, to_validate);
	    (rrset = _rrset_iter_value(&i)); _rrset_iter_next(&i)) {

		if ((s = chase(rrset, support, support_keys, trusted)))
			break;
	}
	if (s == LDNS_STATUS_CRYPTO_BOGUS)
		r = GETDNS_DNSSEC_BOGUS;
	else if (s != LDNS_STATUS_OK)
		r = GETDNS_DNSSEC_INSECURE;
	else
		r = GETDNS_DNSSEC_SECURE;

	ldns_rr_list_free(support_keys);
done_free_to_validate:
	ldns_dnssec_zone_deep_free(to_validate);
done_free_support:
	ldns_dnssec_zone_deep_free(support);
done_free_trusted:
	ldns_rr_list_deep_free(trusted);
	return r;
}				/* getdns_validate_dnssec */

int
priv_getdns_parse_ta_file(time_t *ta_mtime, getdns_list *ta_rrs)
{

	struct gldns_file_parse_state pst;
	struct stat st;
	struct {
		uint16_t id;
		uint16_t flags;
		uint16_t qdcount;
		uint16_t ancount;
		uint16_t nscount;
		uint16_t arcount;
		uint8_t rr[8192]; /* Reasonable max size for a single RR */
	} pkt;
	size_t len, dname_len;
	FILE *in;
	priv_getdns_rr_iter rr_iter;
	getdns_dict *rr_dict = NULL;
	int ta_count = 0;

	if (stat(TRUST_ANCHOR_FILE, &st) != 0)
		return 0;

	if (ta_mtime)
		*ta_mtime = st.st_mtime;

	if (!(in = fopen(TRUST_ANCHOR_FILE, "r")))
		return 0;

	pkt.id = pkt.flags = pkt.qdcount = pkt.nscount = pkt.arcount = 0;
	pkt.ancount = htons(1);

	memset(&pst, 0, sizeof(pst));
	pst.default_ttl = 3600;
	pst.lineno = 1;

	while (!feof(in)) {
		len = sizeof(pkt.rr);
		dname_len = 0;
		if (gldns_fp2wire_rr_buf(in, pkt.rr, &len, &dname_len, &pst))
			break;
		if (len == 0)  /* empty, $TTL, $ORIGIN */
			continue;
		if (gldns_wirerr_get_type(pkt.rr, len, dname_len) 
		    != LDNS_RR_TYPE_DS &&
		    gldns_wirerr_get_type(pkt.rr, len, dname_len)
		    != LDNS_RR_TYPE_DNSKEY)
			continue;
		if (!priv_getdns_rr_iter_init(&rr_iter, (void *)&pkt, sizeof(pkt)))
			break;
		if (!(rr_dict = priv_getdns_rr_iter2rr_dict(NULL, &rr_iter)))
			break;
		if (ta_rrs && getdns_list_append_dict(ta_rrs, rr_dict))
			break;
		getdns_dict_destroy(rr_dict);
		rr_dict = NULL;
		ta_count++;
	}
	if (rr_dict)
		getdns_dict_destroy(rr_dict);
	fclose(in);

	return ta_count;
}

getdns_list *
getdns_root_trust_anchor(time_t *utc_date_of_anchor)
{
	getdns_list *ta_rrs = getdns_list_create();
	(void) priv_getdns_parse_ta_file(utc_date_of_anchor, ta_rrs);
	return ta_rrs;
}

/* dnssec.c */